Composition for patterns.



UNITED STATES PATENT OFFICE.

OSCAR NYGREN, OF MASPETH, NEW YORK, ASSIGNOR TO RICHEY, BROWNE & DONALD,OF MASPETH, NEW YORK.

COMPOSITION FOR PATTERNS.

Specification of Letters Patent.

Patented Jan. 3, 1911.

No Drawing. Application filed April 12, 1906, Serial No. 311,392.Renewed June 4, 1910. Serial No. 565,078.

To all whom it may concern:

Be it known that I, OSCAR NYGREN, a citizen of the United States,residing at Maspeth, in the borough of Queens and State of New York,have invented a new and useful Improvement in Composition for Patterns,of which the following is a specification.

My invention relates to the reproduction or castingof copies of models.In the artistic reproduction of original modeling in high relief in thefine arts or in the decorative arts, it is especially adapted. Inaddition the invention may be applied to the ordinary run of commercialfoundry work, although it is believed to be more especially desirablewhere the model has deep lines and undercut portions.

The improvements deal with the original invention of Richard B. Brownefor surface-hardened, untenacious patterns which are disintegrated orblown away from the mold after the mold has been baked or set. Inreproducing a casting under the Browne method, where the original model,for example, has deep and numerous undercut portions extending atvarious angles and curves, a soft plastic mold (say a glue mold) isfirst made. This mold, owing to its elasticity, can be drawn intact as awhole from the undercut parts of themodel. Into this elastic mold isthen placed a friable, untenacious, or rotten composition in a wetstate, which forms the pattern. After this pattern composition has setthe elastic mold is drawn away and the pattern stands, say for a day ortwo, to dry. It is then coated with a few coats of shellac or othersimilar substance for the purpose of surface-hardening the pattern andpreventing any oil which may be in the molding sand from impregnatingand unduly hardening the pattern composition. I have found that by theaddition of alum to the water, in which the friable pattern compositionis mixed, that its friability or property of disintegrating is increasedmaterially.

In the process as carried out by Mr. Browne he has found that variouscompositions possess, upon drying, this characteris tic of rottenness oreasy crumbling. He has used a composition'of pumice stone and plaster ofparis, for example, with good results. The alum added to the water withwhich such a composition is mixed gives very good results, especially inbaked sand molding after the baking process.

IVhat I claim is:

1. A composition for patterns comprising untenacious friable materialmixed with alum water. i

2. A composition for patterns comprising pumice, plaster of paris, and asolution of alum in water.

3. A composition for patterns comprising pulverized pumice, plaster ofparis, and a solution of alum water.

OSCAR NYGREN.

Witnesses:

J. D. Hose, F. ARUNDEL.

